The diversification, evolution and chemical ecology of a marine radiation of Antarctic sea slugs
I study the incredible diversification, evolution and chemical ecology of a marine mollusc using phylogenomics. The Southern Ocean benthic sea slug, Doris kerguelenensis, was originally described to be a single species that showed reduced dispersal potential. This slug lacks a free-swimming larval stage and can only crawl along the benthos as an adult. More recently however, mitochondrial DNA sequencing has revealed a multitude of highly divergent lineages within that species, representing a species flock comprising over 32 species. I will be using a transcriptome-based exon capture approach to resolve this Antarctic radiation. I’m also examining the link between their chemical defence mechanisms and the cryptic species lineages by filling geographic sampling gaps as well as investigating the relationship between secondary metabolites and gut content. I aim to conduct this research in order to provide information into whether these animals are specialists or generalists. This should help us understand if their diet affects which secondary metabolites are expressed.
Every day biodiversity is being lost at up to 1,000 times the natural rate. With this haunting fact in mind, it is easy to realise how important the field of phylogenomics is in enabling scientists to highlight the underlying processes promoting diversity through reconstructing the evolutionary relationships among taxa. Throughout my thesis, I will utilise these methods to advance an understanding of this Molluscan marine adaptive radiation, with a special focus on evolutionary biology and diversity in the Antarctic, an ecosystem undergoing a period of rapid change.
Moreover, nature is an important source of new pharmaceuticals. Compounds that these nudibranchs have developed for their own defence are of medical interest as over 60% of currently used chemotherapeutic agents are derived or developed from natural sources. Several compounds from this slug have shown useful bioactivity and we hope that phylogenetics can help build a predictive framework with which to guide further pharmaceutical development.